Nanomechanical systems are freely suspended, vibrating nanostructures. Examples include doubly clamped beams or strings, singly clamped nanopillars, or membranes with nanoscale thickness. Their flexural eigenmodes, typically in the megahertz range, are excited by resonant actuation, parametric pumping, or even by thermal noise. The vibrational properties of these tiny objects resemble those of a macroscopic guitar string. However, their response fundamentally differs from their macroscopic counterparts: Nanomechanical resonators can exhibit remarkably high mechanical quality factors, such that the system performs several 100,000 free oscillations before decaying. The dissipation increases with shrinking dimensions, while strong anharmonicities provide a rich nonlinear mechanical response. Nanomechanical resonators are highly sensitive to changes in their environment, and coupling to external degrees of freedom can give rise to strong backaction effects.
In our lab, we are conducting experimental research on nanomechanical systems, with an emphasis on the dissipation, nonlinear dynamics, coupling and coherent control. We employ state of the art cleanroom fabrication technology to process nanoresonators based on strongly pre-stressed silicon nitride, crystalline semiconductor materials such as indium gallium phosphide or gallium arsenide, as well as carbon nanotubes and atomically thin two-dimensional materials. We have pioneered an integrated dielectric transduction scheme to coherently control high Q nanomechanical systems and continuously enhance the functionality of this versatile nano-electromechanical platform, but also explore cavity nano-optomechanical systems, nanoresonator arrays, or nanomechanical charge transport.